UV Exposure Unit

Discussion in 'Alternative Processes' started by Christian Olivet, Nov 30, 2004.

  1. Christian Olivet

    Christian Olivet Member

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    Looking for UV exposure units, I came across a website of a company that manufactures exposure units for screen printing. These are banks of 4 or 6 fluorescent tubes with timer built in and are offered for very reasonable prices.
    I was wandering if anyone have tried any of these. The look pretty decent but wonder if the amount of tubes as well as the separation in between the tubes, and the distance to the glass would make it suitable for alt procesess.
    The website is at: http://westcoastgraphicsllc.com/index.htm
     
  2. photomc

    photomc Member

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  3. jp80874

    jp80874 Subscriber

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    Highly recommend Edwards Engineered Products. http://www.eepjon.com/
    If you buy direct and then at some future date decide you want a larger more sophisticated unit you get your first purchase cost back on the trade.
    Nice deal. Nice product. One man show and a good and helpful person on the phone.

    A satisfied customer,

    John Powers
     
  4. Michael Mutmansky

    Michael Mutmansky Member

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    I think making a fluorescent exposure unit is part of the 'fun' of alternative processes, and something everyone should do at some point. If you are not interested in making your own, there are two sources I would consider, Edwards Engineering Products, and Aristo. The Edwards products are a better value, and have more flexibility, so that would be the direction I'd go.

    Due to the number of lamps in the unit and also the cover glass, I expect you will have very long exposure times on pt/pd and other iron-based printing processes. However, if you could convince them to do a 'custom' with twice the number of lamps, you may be in business. Have them remove the timer, and make sure the cover glass is removeable.

    Also, you need to find out exactly what lamps they are using, as the information they have on the website is insufficient to determine if they lamps are suitable or not. "High UV spectrum" lamps is not really useful to determine the suitability of the lamps.

    One thing about silk screening, I believe the materials used for this are a lot more sensitive than the average alternative process coating, so they don't need to worry about the speed of the exposure unit too much. However, with the very slow processes that most alternative process people are using, even a small reduction in the printing speed will result in a substantial increase in the exposure time required, so it is important to be acutely aware of this when selecting an exposure unit.

    ---Michael

    Let me add one more note. Based on the cost they have listed for the replacement lamps in the FAQ, I expect these lamps are not going to be suitable for many alternative processes. That doesn't mean the unit is useless, but you might have to track down suitable UV lamps for printing. That may actually be harder than you think (or even impossible), depending on the ballasts they have installed in the unit, so be careful.
     
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  5. Christian Olivet

    Christian Olivet Member

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    Thanks a lot for your opinions. Makes sense. I am most times convinced, especially with photography, that one should not save money. It costs more in the end. The Edwards engineering stuff look like the way to go but... The price seems quite expensive. I mean I looked at the local Lowes and Home Depot and it seems I can build one for less than $300. So that may be the way to go.
    The other concern is a vaccum easel. Do you guys know of any source of this on the web.

    Thanks

    Christian
     
  6. sanking

    sanking Member

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    The Edwards Engineering UV units are well made and virtually everyone I know who owns one is satitisfied so they come well recommended.

    But building your own UV bank of lights is really remarkably easy and takes only a modicum of construction skills, and not a lot of time. It is basically simply a question of cutting wood to make a box of the right size, bolting in standard two-tube fixtures, and connecting the wires. And you also need to plan for a small fan. In fact, you can find some working details for building such a unit at the Edwards Engineering site. You might also look at the article I did on UV light sources for some general considerations on building such units. See http://unblinkingeye.com/Articles/Light/light.html

    But there are also other options to UV banks at this point in time, including metal halide lights and platemakers. It really is a very good time to buy used platemakers as many are on the used market because of the change in the pre-press industry to digital output. Outside of local sources for such equpment (graphic art and printing establishiments) check also in the graphic arts and printing section of ebay. Both platemakers and vacuum easels come up very often at attractive prices on ebay.

    Sandy
     
  7. Christian Olivet

    Christian Olivet Member

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    Thanks again
     
  8. Christian Olivet

    Christian Olivet Member

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    I wrote an email to the company asking for the distance between the tubes and the distance to the glass and did mention to them what the intended use was and that eveness of lighting was important. This was the response:

    "The distance between the lamps is 3" and the distance between the glass is 3" as well. I'm not exactly sure of the light refraction as it pertains to what you are doing. I could however build you a custom version with 12 lamps which would create a very even spectrum. This is not required for exposing screens but might be necessary for your needs. It would be about a 125.00 additional cost to do this. Please let me know if I can be of further assistance."

    That is not too bad but I think I will follow the suggestions and build my own.
     
  9. colrehogan

    colrehogan Member

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    I just got my Edwards unit today. I hope to give it a try during my Christmas vacation.
     
  10. photomc

    photomc Member

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    I'm so jealous Diane... :wink:

    Congratulations, can't wait to see some of the work you produce with the new light box..will be interested to hear what your exposure times are with it.
     
  11. Michael Mutmansky

    Michael Mutmansky Member

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    Sandy mentions the commercial units available on the used market...

    A friend of mine just posted one to eBay in the LF cameras section. He has two Nuarc units, and decided to sell one of them. I can vouch for the unit, and the seller.

    It's in Lancaster, PA and is the type of thing that should probably be picked up, but if you are anywhere near Lancaster, it may be worth consideration.

    The one thing that commercial units have over the home made units is the ability to do dodging and burning a bit more easily.


    ---Michael
     
  12. Christian Olivet

    Christian Olivet Member

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    Michael, after thinking a lot about all the options I decided to check the internet and found that there actually was one unit. I got exited and today I noticed another one which must be your friend's.
    Anyway, even though I exceed what I wanted to spend at $695, in the end and the long run, I believe I have made a good investment.

    Thanks.
     
  13. Jorge

    Jorge Inactive

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    YOu got the better one, the one you got is a 26-1Ks as opposed to the 26-1K Michael's friend is selling. The one you bought is the latest model. You are going to love the gizmo.
     
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  15. Michael Mutmansky

    Michael Mutmansky Member

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    Jorge,

    The KS unit is definately newer, and there is some speculation that it may be faster, but I don't think that has been verified by anyone.

    In my book, newer is better, because it should mean that it will last longer before it goes kaput.

    That said, the older unit my friend has will probably only go for $350 or so, which makes is a good bargain for an exposure unit.


    ---Michael
     
  16. Jorge

    Jorge Inactive

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    OTOH Michael, these machines are very simple and easy to repair. I got mine for $200 because the guy said the vacuum did not work. All I did was change some hoses and it was good as new.

    I think Arentz started the rumor that the Ks could be faster, but like you I do not know anybody who has one to verify.

    Who really cares? in the end both the new and old model are great and certainly far better than having to deal with easels etc.
     
  17. Michael Mutmansky

    Michael Mutmansky Member

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    Jorge,

    I've got you beat. I got an Amerigraph unit for $82 because the seller said it didn't work. It works fine, as long as you have the glass in the head properly! (There is a safety interlock to keep it from operating without the safety glass; all I had to do was slide the glass all the way in under the safety switch).

    I now have three exposure units; a home built fluorescent unit, an Amerigraph just like a 26-1K and a BIG Nuarc 40-1K unit. I think I need to get rid of at least one of them, as I'm starting to lose the ability to park in the garage...


    ---Michael
     
  18. Christian Olivet

    Christian Olivet Member

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    Now Jorge, How can you know what I have bought? I am puzzled.

    Anyway it didn't come cheap, but did not want to risk waiting for a cheaper one. Waiting when you want to print if quite painful.

    I don't know how to use this machine. Is there a manual I can get of is it pretty much self explanatory?
     
  19. Jorge

    Jorge Inactive

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    I saw the auction....do you think you are the only who checks e bay for these units?
     
  20. colrehogan

    colrehogan Member

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    I can't wait to give it a try, but Christmas has to come first.

    It will be good to do some printing after spending all day next to a window at work with no sun coming in. :smile:
     
  21. edz

    edz Member

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    They look nice but I suspect won't be able, given their size to really deliver that powerfull/uniform a light.. What's nice about those, however, are the coverage size.. For smaller negative formats like 5x7" what about using a laboratory UV transilluminator? These tend to be very very well made/designed and provide uniform high power UV.
     
  22. jp80874

    jp80874 Subscriber

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    In October APUG member "Peters" was selling an 11x14 Edwards. I chose to buy a new one partly because of the trade up policy and a possible interest in a banquet camera down the road. If Peters' unit is still available it gives you another option.

    John Powers
     
  23. Christian Olivet

    Christian Olivet Member

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    I appreciate everyones participation. I have purchased the Nuarc exposure unit that comes together with vaccum frame and now await delivery.
    I am very eager to print many of my AZO negatives. What process? Kallitype first to learn the coating and the tuning up of the system. Carbon? Sure that too. Platinum, you may ask? definetly. Sooner or later I may incline over on process or another. Maybe not, maybe I will print the negative with the process I feel gets the most of it.
    Will see, for now I have a great learning curve to climb.
     
  24. edz

    edz Member

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    For alt process, if I'm not mistaken one wants 312nm tubes and these, I think, beyond cost also demand some form of UV safety shield--- typically plexiglass. The models I've seen for the spectral sensitivity of these materials indicates that the popular "home brew" black-light lamps are a waste of energy as their UV cutoff is quite high at all wavelenghs were the materials are not as sensitive as with shorter wavelength.. This is why I've suggested we might want to look at the UV transilluminators used for gels.. seems to have similar wants..
     
  25. sanking

    sanking Member

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    I am not sure where you got the idea that one needs tubes of 312 nm for alternative processes but it is incorrect in my opinion. I have actually tested processes such as carbon, gum, kallitype and Pt/Pd. with reptile type tubes that emit radiation in this range and they were actually less efficient than tubes that emit in the 350nm to 420nm range. With most processes the loss of efficiency is due to the fact that plain float glass absorbs virtually all radiation in the 312nm range so it is useless to the process. Even specialty glasses designed for maximum UV transmittance absorb most of the radiation in this range so for all practical purposes, assuming we use glass in our contact printing frames and vacuum easels radiation at 312nm is useless to alternative processes. It is also very dangerous, but since it first and foremost useless to our processes there is no point in belaboring this fact.

    Sandy
     
  26. RussellWelch

    RussellWelch Member

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    I have been using an Olec Al 15 unit for exposure; my standard platinum printing time with dense pyro developed negatives is 3-4 mins using the Olec 1261 bulb. This exposure is much faster than my Black Light bulb unit. The Al 15 is no longer made and the original bulbs no longer supplied by Olec, but third party suppliers have the original bulbs. The Al 15 can also have the capacitors re-wired (4 capacitor model) to accept the new bulbs. The 1261 is called a photopolymer/diazo bulb, when you examine its spectrum (see Olec website) is has an output across the spectrum from 320nm through the visible range, unlike the 1251 which has a variable output. You can find used Olec and Theimer Violux units on ebay, and elsewhere on the net. You can find support for these units from Olec, Douthitt Corp (very helpful) and LexUSA. With the correct bulb these I believe represent the fastest exposure options. These units can be used with or without vacuum frames, so they are adequate for POP and DOP processes.